1. Field of the Invention
The present invention relates generally to optical memory devices and, more particularly, to an optical memory device that can store and transmit data in a purely optical form.
2. Description of the Related Art
Optics has long been considered superior to electronics in computer processing intensive applications. Next generation optical computers require a need for faster memory. There is a move in the networking and switching industries to start doing purely optical transfer of data. But the stopping points in these technologies is the fact that data must be changed from an optical medium to an electronic medium in order for the data to be processed, buffered, and stored. This creates a bottleneck in the data flow process.
Ideally, in an end to end optical data flow, data would stay in its optical format from beginning to end. To accomplish this, there needs to be an advancement in the technologies of optical processors and optical memory. The present invention concerns optical memory.
Current applications of optical memory revolve around compact disc (CD) technology. A laser is used to create pits on a reflective disc. These pits represent the stored data in standard binary form When data retrieval is required a laser is reflected off of the disc while it is spinning. Spinning provides access to all sectors of the disc so that data can be stored in locations outside the range of the laser. This idea originated with magnetic storage of information on removable disc and hard disc devices.
The problems inherent in the use of CDs for storage of data in an optical computer have to do with the slow access times involved with writing and retrieving. To write to a CD the data must be buffered, in a conventional electronic storage device, before being written. Then when accessing the data it must be buffered again before being used by the random access memory and the processor. This puts it in the realm of long term storage medium.
There is also the issue of having moving parts in a computer device. Anything that moves will eventually breakdown due to wear and tear from long term usage. Current hard drive technology is limited because of the same reason. A magnetic disc is spun to all sectors of the drive. Friction from use will eventually bring an end of life to the drive and the possible loss of data that was stored.
There are a number of references that deal with new concepts for optical storage. Many of them still rely on the changing of optical data into electrical data. Others still rely on the idea of spinning a disc in the old CD fashion. Others combine the two ideas. The related art is represented by the following references of interest.
U.S. Pat. No. 4,238,803, issued on Dec. 9, 1980 to Motoyasu Terao et al., describes information recording methods using lasers that require the buffering of data on conventional storage media, thus slowing the process while reading and writing. Terao et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 4,727,528, issued on Feb. 23, 1988 to David C. Wyland, describes an optical data read/write apparatus for use in reading a rotating optical disc having at least one concentric reference track and circular data tracks thereon. Wyland does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 4,877,952, issued on Oct. 31, 1989 to Thirumala R. Halemane et al., describes an optical memory device in which data is written, stored, and read out in optical form without any conversion to electronics. Halemane et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,095,200, issued on Mar. 10, 1992 to Kenichi Matsuda et al., describes an optoelectronic memory, logic, and interconnection device having an optical bistable circuit as an essential element. Matsuda et al. '200 does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,199,087, issued on Mar. 30, 1993 to Gary A. Frazier, describes an optoelectronic integrated circuit chip. Frazier does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,233,556, issued on Mar. 10, 1992 to Kenichi Matsuda et al., describes an optoelectronic memory and logic device that has a function of a reset-set flip flop or an exclusive-OR gate. Matsuda et al. '556 does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,315,105, issued on May 24, 1994 to Kenichi Matsuda et al., describes an optical operational memory device including first and second phototransistors, and a load resistor. Matsuda et al. '105 does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,326,660, issued on Jul. 5, 1994 to Dean B. Parkinson, describes an optical recording structure including a thermally stable structure and a polymeric layer deposited on the substrate comprised of a poly(ester-amide). Parkinson '660 does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,381,362, issued on Jan. 10, 1995 to Xiao An Shen et al., describes a high-speed, high-throughput matched optical filter that allows ro rapid reprogramming to change the reference signal or signals. Shen et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,392,272, issued on Feb. 21, 1995 to Dean B. Parkinson, describes an erasable data storage medium which provides its recording mark or bump by transforming from one morphological state to another upon heating. Parkinson '272 does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 5,951,627, issued on Sep. 14, 1999 to Fouad E. Kiamilev et al., describes an apparatus for calculating a fast Fourier transform for a plurality of data points in a plurality of stages. Kiamilev et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,005,791, issued on Dec. 21, 1999 to Hans Gude Gudesen et al., describes a proximity-addressable optical logic element. Gudesen et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,064,615, issued on May 16, 2000 to Hans Gude Gudesen, describes an optical memory element wherein data are written and read by light incident to the memory element. Gudesen does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,128,110, issued on Oct. 3, 2000 to Jeffrey A. Bulow, describes a programmable optical logic gate. Bulow does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,136,457, issued on Oct. 24, 2000 to Kenjiro Miyano et al., describes a manganese oxide material that can be used as a switching device or as a memory device. Miyano et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,147,889, issued on Nov. 14, 2000 to Thilo Weitzel, describes a device for the optical recording, storage, and readout of information. Weitzel does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,172,926 B1, issued on Jan. 9, 2001 to Phillip M. Drayer, describes an optical storage element for storing data as a packet of photons. Drayer does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,219,160 B1, issued on Apr. 17, 2001 to Per-Erik Nordal et al., describes a multistable optical logic element which undergoes a photo'cycle with several physical states by irradiation with light. Nordal et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,307,779 B1, issued on Oct. 23, 2001 to Frankie F. Roohparvar, describes a synchronous non-volatile flash memory. Roohparvar does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,385,080 B1, issued on May 7, 2002 to Michael J. Heller et al., describes an optical memory system that includes memory cells which utilize synthetic DNA as a component of the information storage mechanism. Heller et al. does not suggest an optical memory device according to the claimed invention.
U.S. Pat. No. 6,392,914 B1, issued on May 21, 2002 to Yoshihiko Kuroki et al., describes a nonlinear coupling oscillator array including two layers in each of which a number of quantum dots as oscillators are arranged two-dimensionally are laid one on another. Kuroki et al. does not suggest an optical memory device according to the claimed invention.
Japan Patent document 2000-322534, published on Nov. 24, 2000, describes an optical recording medium including a memory device and an antenna structure. Japan '534 does not suggest an optical memory device according to the claimed invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus an optical memory device solving the aforementioned problems is desired.